The present invention is generally directed to apparatus for guiding fishing nets and is particularly directed to a neuston net apparatus for guiding a net to be towed at the surface of a body of water.
Sampling the surface of bodies of water has gained increasing attention in the last few years, and has generated a need for a simple but effective neuston net apparatus that will follow the water surface and yield quantitative data as to populations of marine life near the surface. To obtain such quantitative data it is necessary to measure the quantity of water that has been scanned by the mouth opening of the neuston net into which the marine life has been gathered. Such measurement is typically obtained by a flow meter positioned in the mouth of the net at the opening thereof.
However, difficulty has been experienced in obtaining meaningful measurements when using prior art neuston net apparatus because the opening to the mouth of the net defined by the frame of the apparatus to which the net is attached tends to bounce up and down above and below the water surface as the apparatus is towed with a tow line extending to a towing vessel.
Also with prior art neuston net apparatus the tow line used for towing the apparatus tends to disturb the water surface immediately forward of the opening and thus scares many fast moving sea creatures away from the opening before they can be captured in the net.
It is also important that the neuston net apparatus be steered in such a manner in relation to the vessel towing the apparatus that the apparatus is out of the vessels wake so that the water passing through the opening of the apparatus into the mouth of the net is relatively undisturbed by the wake and does not contain effluent from the vessel. This has been accomplished by prior art net apparatus which includes paravanes and an unbalanced bridle yoke attached to the paravanes for steering the apparatus obliquely to the direction in which the apparatus is being towed, and thereby out of the wake of the towing vessel. However, such prior art neuston net apparatus including paravanes still have the aforementioned shortcomings pertaining to (1) the apparatus opening bouncing above and below the water surface, and (2) tow line disturbance of the water immediately forward of the opening scaring fast moving sea creatures away from the opening.